Tona Mod - Prisma

The Tona Mod Prisma is a chronograph Seiko Mod with character. Named for the way light refracts through a prism, the Prisma variant plays with depth and contrast on its multi-register dial — tachymeter bezel framing the whole picture. At 40 mm it sits in the sweet spot for a sport chronograph: assertive on the wrist, never bulky under a cuff. The movement is a Seiko VK63 Meca-Quartz hybrid, which delivers the sweep and feel of a mechanical chronograph stopper with the long-term accuracy of quartz. MedoMods builds every Tona Mod by hand, from bracelet assembly to final timing check.

Specifications

• 40 mm stainless steel case – compact chronograph dimensions that wear well on a broad range of wrist sizes

• Seiko VK63 Meca-Quartz hybrid movement – quartz timekeeping accuracy paired with an instant-reset mechanical chronograph mechanism; no battery anxiety, no compromise on precision

• Sapphire crystal with Super-LumiNova – scratch-resistant glass over luminous indices; the subdials stay readable in dim conditions

• Screw-down crown & 5 ATM water resistance – secure seal for daily wear, rain, and casual water exposure

• Tachymeter bezel & chronograph function – measure speed or elapsed time directly from the bezel scale; pushers feel crisp and positive

• 904L stainless steel bracelet – adjustable from 14.5 to 22 cm, 20 mm lug width; the same steel grade used in high-end Swiss sports watches for its corrosion resistance and polishability

The Meca-Quartz Advantage

Unlike a fully mechanical chronograph, the VK63 resets to zero with a snap and holds the stopped time indefinitely — useful whether you are timing a lap or just checking elapsed minutes in a meeting. Hand-assembled by MedoMods and shipped from within the EU, the Tona Mod Prisma arrives ready to wear, no customs fees attached.

Ordering and delivery

• Every watch comes with a 2-year warranty from delivery. It covers manufacturing defects and functional problems under normal use. It doesn't cover scratches, damage from opening the watch, or water damage.
• 10–12 days after ordering
• 14-day withdrawal period. The period starts on receipt. For deliveries to the UK, US and Australia, we offer 14-day returns.